Sensor equipment includes a sensor device with a sensing portion. The sensing portion is exposed outside to detect an object. The sensor device has a connector for connecting to an external circuit. The connector is protected with an electric insulation coating. The sensor equipment is, for example, disclosed in Japanese Patent Application Publication No. 2000-2572. The sensor equipment is a thermal type airflow sensor having a semiconductor substrate.
The airflow sensor has an airflow detection device as the sensor device. The airflow detection device is formed of a silicon substrate. A heat generating resistor, i.e., a heater as the sensing portion is formed on the surface of the substrate. When the air flows on the surface of the airflow detection device, the heat radiation of the heater is changed. This change is detected as a resistance change so that the airflow amount is measured by processing the resistance change with an electric circuit.
Here, the airflow detection device and the electric circuit are connected with a bonding wire electrically. An electric connector of the airflow detection device is coated with a sealing member such as an electric insulation member for protecting from erosion and the like.
In the prior art, the sealing member is made of gel. Therefore, when the gel of the sealing member is adhered to the heater of the airflow detection device, heat radiation of the heater is reduced. Thus, the airflow detection sensitivity of the device is reduced. Accordingly, the airflow detection device includes a stopper for preventing the sealing member from removing. The stopper is formed on the airflow detection device.
However, the sealing member is deteriorated with time, and therefore, the sealing member flows outside or flows on the surface of the airflow detection device. Thus, airflow detection sensitivity of the sensor equipment is reduced. This problem is occurred not only in the airflow sensor but also in a sensor having a sensing portion exposed outside and an electric connector protected with an electric insulation coating.